第1708题：直角坐标转极坐标
将直角坐标 (22,−22)(2\sqrt{2},-2\sqrt{2})(2√2,−2√2) 化成极坐标得到( ).
A. (2,7π6)(2,\dfrac{7\pi}{6})(2,67π)
B. (2,7π6)(2,\dfrac{7\pi}{6})(2,67π)
C. (2,7π4)(2,\dfrac{7\pi}{4})(2,47π)
D. (4,7π4)(4,\dfrac{7\pi}{4})(4,47π)
